Information insertion method, information extraction method, and information extraction apparatus using dot-based information robust to geometric distortion

ABSTRACT

An information insertion method, an information extraction method, and an information extraction apparatus using dot-based information are provided herein. The information extraction apparatus includes an identification unit and an extraction unit. The identification unit identifies a set of at least one dot output to a target. The extraction unit extracts information from the set of at least one dot.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2015-0013371, filed Jan. 28, 2015, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

1. Technical Field

Embodiments of the present invention relate generally to imageprocessing and, more particularly, to an information insertion method,an information extraction method, and an information extractionapparatus using dot-based information robust to geometric distortion.

2. Description of the Related Art

As the technical capabilities of companies improve, cases wherehigh-tech industrial technologies are externally leaked continue tooccur. The leakage of technology is chiefly performed by insiders whointelligently make bad use of the weak points of existing securitysystems.

Accordingly, there is a need for a technology that is capable ofinserting barely perceptible or imperceptible information into a target,such as a printed confidential document or a monitor screen, andextracting the inserted information from the target when the target isexternally divulged.

In relation to the insertion of information into a target, there is amethod of inserting information into a target by controlling thelocation and direction of a dot pattern inserted into the target. Arelated technology using this method includes Korean Patent No.10-0906457 entitled “Information Input/Output Method Using Dot Pattern.”In this technology, reference lattice lines are present on the surfaceof a medium in a vertical direction and a horizontal direction. A dot isdisposed at a location that corresponds to a specific distance anddirection for a virtual lattice dot, that is, the intersection of thereference lattice lines, and information is inserted into the location.In other words, the distance and direction of a dot for a virtuallattice dot represents information. However, this technology isproblematic in that it requires a reference lattice dot for indicating areference lattice line and it is not robust to various geometricmodifications.

Another related technology regarding the insertion of information into atarget includes Korean Patent No. 10-0403204 entitled “Method andApparatus for Embedding and Extracting Watermark for Binary Text.” Inthis technology, a document is converted into a binary image, a line inwhich letters are written is detected in the binary image, andinformation is inserted by deforming information in the detected line.However, this method is problematic in that it is difficult to deforminformation in a line in an actual environment in which information isinserted and extracted and that the method is not robust to variousgeometric modifications.

As described above, the above related technologies have limitations onactually inserting meaningful information into a target and extractingmeaningful information from a target.

SUMMARY

At least some embodiments of the present invention are directed to theprovision of a method, apparatus, and system for inserting informationinto a target and extracting information from the target.

At least some embodiments of the present invention are intended toprovide a method, apparatus, and system using a barely perceptible formor an imperceptible form in the insertion of information and theextraction of information.

At least some embodiments of the present invention are intended toprovide a method, apparatus, and system for performing correction ongeometric distortion that has been applied to an image of a target inthe extraction of information.

According to an aspect of the present invention, there is provided aninformation insertion method, including: receiving information;converting the information into a set of at least one dot; andoutputting the set of at least one dot to a target.

Outputting the set of at least one dot may include converting the dataof the target so that the set of at least one dot can be inserted intothe target.

Outputting the set of at least one dot may include adding a substance,indicative of the set of at least one dot, to the target.

The substance may be perceptible under a predetermined type of light.

Converting the information may include: splitting the information intoat least one bit string of a predetermined length; for each bit stringof the at least one bit string, adding a dot pattern that corresponds tothe each bit string among a plurality of different dot patterns as a dotof the set of at least one dot; and setting the location of each dot ofthe set of at least one dot.

The at least one dot may be disposed at irregular intervals.

Outputting the set of at least one dot may include: identifying a regionof the target to which the set of at least one dot is to be output;converting the set of at least one dot into a barely perceptible form oran imperceptible form in terms of at least one of color and texture ofthe region; and outputting the converted set of at least one dot to theregion.

According to another aspect of the present invention, there is providedan information extraction method, including: identifying a set of atleast one dot output to a target; and extracting information from theset of at least one dot.

Identifying the set of at least one dot may include detecting the set ofat least one dot within the target by analyzing data of the target.

Identifying the set of at least one dot may include: capturing an imageof the target; and detecting the set of at least one dot in the capturedimage.

The information extraction method may further include emitting apredetermined type of light, which makes a substance, output to thetarget, perceptible, to the target.

The information extraction method may further include performingcorrection on geometric distortion applied to the set of at least onedot.

Performing correction on the geometric distortion may include performingcorrection on projection and rotation distortion applied to the set ofat least one dot; and performing correction on the projection androtation distortion may include detecting four reference dots in aregion of the set of at least one dot and performing correction on theprojection and rotation distortion using the four reference dots.

Performing correction on the projection and rotation distortion mayinclude generating a set of a horizontal line and a set of a verticalline passing through the at least one dot, extracting two horizontallines from the set of a horizontal line, and extracting two verticallines from the set of a vertical line; the four reference dots may bethe intersections of the two horizontal lines and the two verticallines; the two horizontal lines may include a horizontal line closest toan origin and a horizontal line farthest from the origin; and the twovertical lines may include a vertical line closest to the origin and avertical line farthest from the origin.

Performing correction on the projection and rotation distortion mayinclude performing Hough transform on at least one central coordinate ofthe at least one dot; and horizontal lines and vertical lines passingthrough the at least one dot may be horizontal lines and a verticallines passing through the at least one central coordinate to which theHough transform has been applied.

Generating the set of horizontal lines and the set of vertical lines mayinclude: detecting at least one rectilinear line passing through the atleast one dot; detecting two angle ranges in which the rectilinear linesare maximally present; and including the rectilinear lines, whichcorresponds to one of the two angle ranges, in the set of horizontallines or the set of vertical lines.

The information extraction method may further include performingcorrection on size distortion applied to the set of at least one dot;and performing the correction on the size distortion may include:generating a cumulative value in a horizontal and a cumulative value ina vertical direction by accumulating values of the central coordinatesof the at least one dot in the horizontal direction and the verticaldirection; detecting a horizontal period and a vertical period, inwhich, the at least one dot appears, by analyzing the cumulative valuein the horizontal direction and the cumulative value in the verticaldirection; and correcting an image of the set of at least one dot sothat the horizontal period and the vertical period match an originalperiod.

The horizontal period and the vertical period may be detected byfrequency domain analysis of the cumulative value in the horizontaldirection and the cumulative value in the vertical direction.

Extracting the information may include: for each dot of the set of atleast one dot, determining a dot pattern that corresponds to the eachdot among a plurality of different dot patterns; and using the value ofa bit string of the determined dot pattern as at least part of theinformation.

According to still another aspect of the present invention, there isprovided an information extraction apparatus, including: anidentification unit configured to identify a set of at least one dotoutput to a target; and an extraction unit configured to extractinformation from the set of at least one dot.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other targets, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram illustrating the operation of an informationinsertion apparatus according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating the operation of an informationextraction apparatus according to an embodiment of the presentinvention;

FIG. 3 is a diagram illustrating the configuration of an informationinsertion apparatus according to an embodiment of the present invention;

FIG. 4 is a flowchart illustrating an information insertion methodaccording to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a method of converting informationinto a set of at least one dot according to an example;

FIG. 6 is a diagram illustrating a plurality of dot patterns accordingto an example;

FIG. 7 is a diagram illustrating a dot pattern having no form accordingto an example;

FIG. 8 is a diagram illustrating a plurality of dot patterns of a bitstring having a length of 2 according to an example;

FIG. 9 is a diagram illustrating a plurality of dot patterns having twoor more colors according to an example;

FIG. 10 is a flowchart illustrating a method of outputting a set of atleast one dot to a target according to an example;

FIG. 11 is a diagram illustrating a set of at least one dot according toan example;

FIG. 12 is a diagram illustrating a target into which a set of at leastone dot has been inserted according to an example;

FIG. 13 is a diagram illustrating the configuration of an informationextraction apparatus according to an embodiment of the presentinvention;

FIG. 14 is a flowchart illustrating an information extraction methodaccording to an embodiment of the present invention;

FIG. 15 is a flowchart illustrating a method of identifying a set of atleast one dot output to a target according to an example;

FIG. 16 is a flowchart illustrating a method of performing correction ongeometric distortion that has been applied to a set of at least one dotaccording to an example;

FIG. 17 is a flowchart illustrating a method of performing correction onprojection and rotation distortion that have been applied to a set of atleast one dot according to an example;

FIG. 18 is a view illustrating a process of performing correction onprojection and rotation distortion that have been applied to a set of atleast one dot according to an example;

FIG. 19 is a flowchart illustrating a method of performing correction onsize distortion that has been applied to a set of at least one dotaccording to an example;

FIG. 20 is a view illustrating a process of performing correction onsize distortion that has been applied to a set of at least one dotaccording to an example;

FIG. 21 is a flowchart illustrating a method of extracting informationfrom a set of at least one dot according to an example;

FIG. 22 is a diagram illustrating an electronic device that implementsan information insertion apparatus according to an embodiment of thepresent invention; and

FIG. 23 is a diagram illustrating an electronic device that implementsan information extraction apparatus according to an embodiment of thepresent invention.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings. It should be appreciatedthat these embodiments are different but are not necessarily exclusive.The terms used in these embodiments should be defined not simply by thenames of the terms but by their meanings and the overall context of thepresent specification. In these embodiments, the connection between twocomponents or portions may include not only the direct connectiontherebetween but also the indirect connection therebetween. Throughoutthe drawings, the same reference numerals are used to designate the sameor similar components or portions.

FIG. 1 illustrates the operation of an information insertion apparatusaccording to an embodiment of the present invention.

The information insertion apparatus 100 may insert information into atarget.

The information may be inserted in the form of a set of at least onedot. In other words, the information insertion apparatus 100 may be adot-based information insertion apparatus using a dot in the insertionof information.

The information insertion apparatus 100 may receive information. Theinformation insertion apparatus 100 may generate a target, into whichinformation has been inserted, by inserting the information into thetarget.

The target may include electronic data and an object. For example, thetarget may be electronic data, such as an image, a moving image, aphotograph, an electronic document, or a monitor screen. Furthermore,the target may be an actual object, such as a photograph, a film, orprinted matter.

The information may refer to content that a user attempts to insert intothe target. The information may be information about the owner of atarget, information about time, and information about a location. Inthis case, the time may refer to the time at which information isinserted into a target. The location may refer to the location of a useror the information insertion apparatus 100 at which the information isinserted into the target.

The information insertion apparatus 100 may represent information usinga set of at least one dot. The set of at least one dot may be a set ofat least one dot disposed on a two-dimensional plane. Each dot of theset of at least one dot may have coordinates. The coordinates may berelative values for the origin of the two-dimensional plane.

Alternatively, the set of at least one dot may be a set of at least onedot within an image. Each dot of the set of at least one dot may havecoordinates within the image. The coordinates may be relative values forthe origin of the image. The image may be an image of the set of atleast one dot or an image of the target.

The set of at least one dot may have regular intervals or irregularintervals. In other words, at least one dot may be disposed at regularintervals or irregular intervals.

The information insertion apparatus 100 may convert the set of at leastone dot into color and texture that match the target.

The information insertion apparatus 100 may output a set of at least onedot to the target. The information insertion apparatus 100 may generatethe target, into which information has been inserted, by outputting aset of at least one dot to the target.

The target into which information has been inserted may includeelectronic data and an object. For example, the target may be electronicdata, such as an electronic document on which an image of a set of atleast one dot has been printed, or a monitor screen on which an image ofa set of at least one dot has been displayed. Furthermore, the targetmay be an object, such as printed matter on which an image of a set ofat least one dot has been printed.

FIG. 2 illustrates the operation of an information extraction apparatusaccording to an embodiment of the present invention.

The information extraction apparatus 200 may extract information from atarget into which information has been inserted.

The information may be inserted in the form of a set of at least onedot. The target into which the information has been inserted may haveinformation inserted in the form of a set of at least one dot. In otherwords, the information extraction apparatus 200 may be a dot-basedinformation extraction apparatus for extracting information insertedusing a dot.

The information extraction apparatus 200 may identify a set of at leastone dot output to a target. The information extraction apparatus 200 maydetect information from the identified set of at least one dot.

A target into which information has been inserted may include electronicdata and an object. For example, the target may be electronic data, suchas an electronic document or a monitor screen. Furthermore, the targetmay be an actual object, such as printed matter.

If the target is electronic data, the information extraction apparatus200 may receive the electronic data of the target. The informationextraction apparatus 200 may detect information by analyzing a set of atleast one dot in the electronic data of a target.

If the target is an object, the information extraction apparatus 200 maygenerate the electronic data of the target by photographing the target.If the electronic data of the target is generated, the informationextraction apparatus 200 may detect information by analyzing a set of atleast one dot in the electronic data of the target.

In order to photograph the target, an image photographer, such as acamera, a scanner, a smart phone or an infrared camera, may be used. Theimage photographer may be part of the information extraction apparatus200. In this case, the photographing of the target may be a task ofacquiring the data of an image of the target.

Information may refer to content inserted into the target by a user. Theinformation may be information about the owner of a target, informationabout time, and information about a location. In this case, the time mayrefer to the time at which the information is inserted into the target.The location may refer to the location of a user or the informationinsertion apparatus 100 when information is inserted into the target.

In the target, the information may be represented in the form of a setof at least one dot. The set of at least one dot may be a set of atleast one dot disposed on a two-dimensional plane. Each dot of the setof at least one dot may have coordinates. The coordinates may berelative values for the origin of the two-dimensional plane.

Alternatively, the set of at least one dot may be a set of at least onedot within an image. In this case, the image including the set of dotsmay be an image indicative of the target, or may be an image extractedfrom the data of the target using a predetermined image extractionmethod. Each dot of the set of at least one dot may have coordinateswithin the image. The coordinates may be relative values for the originof the image.

The set of at least one dot may have regular intervals or irregularintervals. In other words, the at least one dot may be disposed atregular intervals or irregular intervals.

The information extraction apparatus 200 may extract information from aset of at least one dot that matches the color and texture of thetarget.

FIG. 3 is a diagram illustrating the configuration of an informationinsertion apparatus according to an embodiment of the present invention.

The information insertion apparatus 100 may include a reception unit310, a generation unit 320, and an output unit 330.

As illustrated in FIG. 3, the information insertion apparatus 100according to the present embodiment may include the reception unit 310,the generation unit 320, and the output unit 330. According to anembodiment, at least some of the reception unit 310, the generation unit320, and the output unit 330 may be program modules, and may communicatewith an external device or system. These program modules may be includedin the information insertion apparatus 100 in the form of an operatingsystem, an application program module, and other program modules, andmay be physically stored in various known storage devices. Furthermore,at least some of the program modules may be stored in a remote storagedevice that is capable of communicating with the information insertionapparatus 100. Although the program modules may include a routine, asubroutine, a program, a target, a component, and a data structure thatperform a specific task or execute a specific abstraction data type tobe described later according to an embodiment of the present invention,they are not limited thereto. The program modules may includeinstructions that are executed by at least one processor of theinformation insertion apparatus 100.

The functions of the reception unit 310, the generation unit 320, andthe output unit 330 according to an example are described in detailbelow with reference to FIG. 4.

FIG. 4 is a flowchart illustrating an information insertion methodaccording to an embodiment of the present invention.

At step 410, the reception unit 310 may receive information.

At step 420, the generation unit 320 may convert the information into aset of at least one dot. The generation unit 320 may generate the set ofat least one dot indicative of the information.

The set of at least one dot may be represented in the form of an image.The generation unit 320 may generate an image including the at least onedot indicative of the information.

For example, a method of converting information into a set of at leastone dot is described in detail below with reference to FIG. 5.

At step 430, the output unit 330 may output a set of at least one dot tothe target.

The output unit 330 may output an image, including at least one dot, tothe target.

For example, a method of outputting a set of at least one dot to atarget is described in detail below with reference to FIG. 10.

Hereinafter, the terms “set of at least one dot,” “image of the target”and “image including at least one dot” may be used as having the samemeaning according to circumstances, and may be interchangeably usedwithout a particular mention.

As described above, the target may be electronic data. If the target iselectronic data, the output unit 330 may convert the data of the targetso that the set of at least one dot can be inserted into the target atstep 430. Alternatively, the output unit 330 may convert the data of thetarget so that an image including the set of at least one dot can beinserted into the target. Through this conversion, the data of thetarget may represent a set of at least one dot, together with theexisting target.

Furthermore, as described above, the target may be an object. If thetarget is an object, the output unit 330 may represent a set of at leastone dot in the target at step 430. The output unit 330 may add asubstance, indicative of the set of at least one dot, to the target. Forexample, the substance may be the toner or ink of a printer. A toner orink of a predetermined color may be used to represent the set of atleast one dot.

The output unit 330 may add a substance, which is perceptible under apredetermined type of light, to the target. In other words, thesubstance that has been added to the target and that is indicative ofthe set of at least one dot may not be identified by a user and theinformation extraction apparatus 200 under a common environment. Theuser and the information extraction apparatus 200 may identify thesubstance that has been added to the target and that is indicative ofthe set of at least one dot only when a predetermined type of light isshined on the target.

The output unit 330 may display the set of at least one dot on thetarget using a printing method. The output unit 330 may be a printer, ormay include a printer. Furthermore, the output unit 330 may control theprinter so that the set of at least one dot is displayed on the target.In this case, the information insertion apparatus 100 may furtherinclude a printer.

FIG. 5 is a flowchart illustrating a method of converting informationinto a set of at least one, dot according to an example.

Step 420 described above with reference to FIG. 4 may include thefollowing steps 510, 520 and 530.

Information may be represented in the form of at least one bit string.

At step 510, the generation unit 320 may split information into at leastone bit string of a predetermined length. The predetermined length mayrefer to the number of bits of a bit string. For example, the generationunit 320 may split the information into bit strings each having 1 bit.Alternatively, the generation unit 320 may split the information intobit strings each having two bits.

At step 520, the generation unit 320 may add, for each bit string of theat least one bit string, a dot pattern that corresponds to the each bitstring among a plurality of different dot patterns as a dot of the setof at least one dot.

The plurality of dot patterns may have different forms of dots. Aplurality of dot patterns according to an example is described in detailbelow with reference to FIGS. 6 to 9.

A dot pattern corresponding to a bit string may be a dot patterncorresponding to a value indicative of the bit string.

If the length of a bit string is n, the number of the plurality of dotpatterns may be 2^(n). A plurality of dot patterns may be indicative ofdifferent values. For example, if the length of a bit string is 1,values that may be represented as a length of 1 bit may be “0” and “1.”That is, two values may be represented as a length of 1 bit.

If the length of a bit string is 1, the first dot pattern of theplurality of dot patterns may correspond to a value “0”, and the seconddot pattern of the plurality of dot patterns may correspond to a value“1.” If the value of a specific bit string is “0”, a dot patterncorresponding to the bit string may be a dot pattern corresponding tothe value “0.” If the value of another bit string is “1”, a dot patterncorresponding to the bit string may be a dot pattern corresponding tothe value “1.”

At step 530, the generation unit 320 may set the location of each of theset of at least one dot. The generation unit 320 may set the coordinatevalues of each of the set of at least one dot.

The generation unit 320 may dispose the at least one dot within an imageat regular intervals. If the at least one dot is disposed at regularintervals, the information extraction apparatus 200 may obtain thelocation of each of the set of at least one dot within the image via apredetermined rule, predetermined information, or predeterminedcomputation.

The generation unit 320 may dispose the at least one dot within an imageat irregular intervals. If the at least one dot is disposed at irregularintervals, the information extraction apparatus 200 may identify eachdot of the set of at least one dot within the image via a predeterminedmethod.

FIG. 6 illustrates a plurality of dot patterns according to an example.

FIG. 6 illustrates a dot pattern corresponding to the value “0” of a bitstring and a dot pattern corresponding to the value “1” of the bitstring.

As illustrated in FIG. 6, a plurality of dot patterns may have a formindicative of a dot. The plurality of dot patterns may be different inat least one of form, size, color, and alpha. FIG. 6 illustrates two dotpatterns having different forms and sizes.

A plurality of dot patterns may be placed at the center of a regionhaving a predetermined size.

A plurality of dot patterns may have a predetermined color value. Thegeneration unit 320 may use a predetermined color value only to displaya plurality of dot patterns in an image. For example, the plurality ofdot patterns may have the red, green and blue (RGB) color value“0x000000” in hexadecimal. The generation unit 320 may use apredetermined color value only to display a plurality of dot patterns,and may convert another portion of an image having a predetermined colorvalue other than the plurality of dot patterns into another valuesimilar or approximate to the predetermined color value. For example,the generation unit 320 may change the color value of a portion, whichbelongs to the data of the target and which corresponds to “0x000000,”into “0x010101.”

FIG. 7 illustrates a dot pattern not having a form according to anexample.

FIG. 7 illustrates a dot pattern corresponding to the value “0” of a bitstring and a dot pattern corresponding to the value “1” of the bitstring. As illustrated in FIG. 7, the dot pattern corresponding to thevalue “0” may not have a form. One of a plurality of dot patterns maynot have a form.

In order to use a dot pattern not having a form, the generation unit 320may dispose at least one dot within an image at regular intervals. Theinformation extraction apparatus 200 may obtain the location of each dotof a set of at least one dot within an image via computation. Once thelocation of each dot has been obtained, the information extractionapparatus 200 may set a value, represented by a dot pattern not having aform, as the value of a bit string corresponding to the obtainedlocation if a dot is not detected at the obtained location.

Alternatively, a dot pattern not having a form may have a value that isnot seen by a naked eye but is represented and identified in terms ofdata.

FIG. 8 illustrates a plurality of dot patterns of a bit string having alength of 2 according to an example.

FIG. 8 illustrates a dot pattern corresponding to the bit string value“00,” a dot pattern corresponding to the bit string value “01,” a dotpattern corresponding to the bit string value “10,” and a dot patterncorresponding to the bit string value “11.”

As illustrated in FIG. 8, a plurality of dot patterns may have formsindicative of a dot. The plurality of dot patterns may be different inat least one of form, size, color, and alpha. FIG. 8 illustrates fourdot patterns having different forms and sizes.

FIG. 9 illustrates a plurality of dot patterns each having two or morecolors according to an example.

FIG. 9 illustrates a dot pattern corresponding to the value “0” of a bitstring and a dot pattern corresponding to the value “1” of the bitstring.

In these dot patterns, a portion filled with a dot may represent a darkportion, a portion not filled with any dot may represent a whiteportion, and a hatched portion may represent a transparent portion.

In order to distinguish corresponding content from other content withinan image, each of a plurality of dot patterns may include two or morecolors and include a transparent color. Since each pattern includes twoor more colors, the information extraction apparatus 200 may easilyidentify at least one dot even when the at least one dot is disposed atirregular intervals within the image.

FIG. 10 is a flowchart illustrating a method of outputting a set of atleast one dot to a target according to an example.

At step 1010, the output unit 330 may identify a region of a target towhich a set of at least one dot is to be output. The output unit 330 maydetermine a region of the target to which a set of at least one dot isto be output.

At step 1020, the output unit 330 may convert the set of at least onedot into a form that matches at least one of the color and texture ofthe target. The output unit 330 may convert the set of at least one dotinto a barely perceptible form or an imperceptible form in terms of atleast one of the color and texture of the target.

The output unit 330 may convert the set of at least one dot into abarely perceptible form or an imperceptible form for naked eyes in termsof at least one of the color and texture of the target. In this case,the barely perceptible form or imperceptible form may refer to a formthat is barely identified or cannot be identified by the naked, eyes ofa user but can be identified by the information extraction apparatus200. For example, if the color value of the background color of anelectronic document is the hexadecimal number “0x000000”, the outputunit 330 may convert the color value of the color of a set of at leastone dot into the hexadecimal number “0x010101.”

The conversion of a form may be performed on the region identified ordetermined at step 1010. The output unit 330 may convert the set of atleast one dot into a barely perceptible form or an imperceptible form interms of at least one of the color and texture of the region. Forexample, the output unit 330 may convert the set of at least one dotinto a color that is similar to or the same as the color of the region,and may convert the set of at least one dot into texture that is similarto or the same as the texture of the region.

At, step 1030, the output unit 330 may output the converted set of atleast one dot to the target.

The output to the target may be performed on the region identified ordetermined at step 1010. The output unit 330 may output the convertedset of at least one dot to the region.

FIG. 11 illustrates a set of at least one dot according to an example.

As illustrated in FIG. 11, a set of at least one dot may be a set of atleast one dot disposed on a two-dimensional plane. Furthermore, the setof at least one dot may be a set of at least one dot within an image.

FIG. 12 illustrates a target into which a set of at least one dot hasbeen inserted according to an example.

As illustrated in FIG. 12, a set of at least one dot may be insertedinto an electronic image. The target may be an image indicative of text.A set of at least one dot indicative of information may be inserted asthe background of an image.

As illustrated in FIG. 12, if the target is an image, a moving image, aphotograph, an electronic document or a monitor screen, the output unit330 may insert a set of at least one dot as the background of thetarget.

FIG. 13 is a diagram illustrating the configuration of an informationextraction apparatus 100 according to an embodiment of the presentinvention.

The information extraction apparatus 200 may include an identificationunit 1310, a correction unit 1320, and an extraction unit 1330.

As illustrated in FIG. 13, the information extraction apparatus 200according to the present embodiment may include the identification unit1310, the correction unit 1320, and the extraction unit 1330. Accordingto an embodiment, at least some of the identification unit 1310, thecorrection unit 1320, and the extraction unit 1330 may be programmodules, and may communicate with an external device or system. Theprogram modules may be included in the information extraction apparatus200 in the form of an operating system, an application program module,or other program modules, and may be physically stored in various knownstorage devices. Furthermore, at least some of the program modules maybe stored in a remote storage device that is capable of communicatingwith the information extraction apparatus 200. Although the programmodules may include a routine, a subroutine, a program, a target, acomponent, and a data structure that perform a specific task or executea specific abstraction data type to be described later according to anembodiment of the present invention, they are not limited thereto. Theprogram modules may include instructions that are executed by at leastone processor of the information extraction apparatus 200.

The functions of the identification unit 1310, the correction unit 1320,and the extraction unit 1330 according to an example are described indetail below with reference to FIG. 14.

FIG. 14 is a flowchart illustrating an information extraction methodaccording to an embodiment of the present invention.

In the following description, a set of at least one dot indicative ofinformation may have been inserted into a target by the informationinsertion apparatus 100.

At step 1410, the identification unit 1310 may identify the set of atleast one dot output to the target.

For example, the identification unit 1310 may identify a predetermineddot pattern in the target as a dot. Furthermore, the identification unit1310 may identify an object on a predetermined location in an image ofthe target as a dot. Furthermore, the identification unit 1310 mayidentify a part of an image of the target having a predetermined form,shape, color, or alpha as a dot.

The identification unit 1310 may extract an image only consisting of theset of at least one dot from the image of the target.

The identification unit 1310 may obtain an image, including the set ofat least one dot, from the target, and may obtain the set of at leastone dot by thresholding the obtained image. For example, theidentification unit 1310 may identify a predetermined region within theobtained image as a set of at least one dot. In this case, thepredetermined region may be a region whose color value or alpha value isequal to or larger than a predetermined value, a region whose colorvalue or alpha value is equal to or smaller than a predetermined value,or a region whose color value or alpha value falls within apredetermined range.

At step 1420, the correction unit 1320 may correct geometric distortionthat has been applied to the set of at least one dot.

Geometric distortion occurring in a process of adding or obtaining theset of at least one dot may be corrected by the correction unit 1320.

A method of performing correction on geometric distortion that has beenapplied to a set of at least one, dot according to an example isdescribed in detail later with reference to FIG. 16.

At step 1430, the extraction unit 1330 may extract information from theset of at least one dot.

A method of extracting information from a set of at least one dotaccording to an example is described in detail later with reference toFIG. 21.

As described above, the target may be electronic data. If the target iselectronic data, the identification unit 1310 may receive the electronicdata of the target from an external another device at step 1410.Furthermore, the identification unit 1310 may detect a set of at leastone dot within the target by analyzing the data of the target.

Furthermore, as described above, the target may be an object. A methodby which the identification unit 131 identifies a set of at least onedot output to a target if the target is an object is described in detailbelow with reference to FIG. 15.

FIG. 15 is a flowchart illustrating a method of identifying a set of atleast one dot output to a target according to an example.

Step 1410 described above with reference to FIG. 14 may include thefollowing steps 1510, 1520 and 1530.

At step 1510, the identification unit 1310 may emit a predetermined typeof light, which makes a substance, output to the target, perceptible, tothe target.

As described above, a set of at least one dot may be added to the targetas a substance that is perceptible under a predetermined type of light.In this case, the predetermined type of light may need to be projectedonto the target so that the set of at least one dot is exposed out ofthe target.

The identification unit 1310 may be a lighting device, or may include alighting device. Furthermore, the identification unit 1310 may controlthe lighting device so that a predetermined type of light that makes asubstance, output to the target, perceptible is emitted to the target.In this case, the information extraction apparatus 200 may furtherinclude a lighting device.

At step 1520, the identification unit 1310 may capture an image of thetarget.

The identification unit 1310 may be an image photographer, or mayinclude an image photographer. Alternatively, the identification unit1310 may control an image photographer so that it captures an image ofthe target. In this case, the information extraction apparatus 200 mayfurther include an image photographer. The image photographer mayinclude a camera, a scanner, a smart phone, or an infrared camera.

At step 1530, the identification unit 1310 may detect the set of atleast one dot in the captured image.

FIG. 16 is a flowchart illustrating a method of performing correction ongeometric distortion that has been applied to a set of at least one dotaccording to an example.

Step 1420 described above with reference to FIG. 14 may include thefollowing steps 1610 and 1620.

At step 1610, the correction unit 1320 may perform correction onprojection and rotation distortion that have been applied to a set of atleast one dot.

A method of performing correction on projection and rotation distortionthat have been applied to a set of at least one dot according to anexample is described in detail below with reference to FIG. 17.

At step 1620, the correction unit 1320 may perform correction on sizedistortion that has been applied to a set of at least one dot.

A method of performing correction on size distortion that has beenapplied to the set of at least one dot according to an example isdescribed in detail later with reference to FIG. 19.

FIG. 17 is a flowchart illustrating a method of performing correction onprojection and rotation distortion that have been applied to a set of atleast one dot according to an example.

Step 1610 described above with reference to FIG. 16 may include thefollowing steps 1710, 1720, 1730, 1740, 1750 and 1760.

At step 1710, the correction unit 1320 may perform Hough transform on atleast one central coordinate of the identified at least one dot.

At step 1720, the correction unit 1320 may generate a set of ahorizontal line and a set of a vertical line that pass through at leastone dot.

The horizontal line and the vertical line that pass through the at leastone dot may be rectilinear lines that pass through at least one centralcoordinate of the at least one dot to which Hough transform has beenapplied. For example, the horizontal line and the vertical line thatpass through the at least one dot may be rectilinear lines that passthrough two or more central coordinates of the at least one centralcoordinate to which Hough transform has been applied. Horizontal linesand vertical lines passing through the at least one dot may behorizontal lines and vertical lines passing through the at least onecentral coordinate to which the Hough transform has been applied.

Step 1720 may include the following steps 1721, 1722 and 1723.

At step 1721, the correction unit 1320 may detect at least onerectilinear line that passes through the at least one dot.

The rectilinear line that passes through the at least one dot may passat least one central coordinate of the at least one dot to which Houghtransform has been applied. For example, the rectilinear line thatpasses through the at least one dot may pass two or more centralcoordinates of the dots to which Hough transform has been applied.

At step 1722, the correction unit 1330 may detect two angle ranges inwhich rectilinear lines are maximally present.

The two angle ranges may be an angle range for vertical lines and anangle range for horizontal lines. The correction unit 1330 may detecttwo angle ranges, in which the rectilinear lines are maximally present,as an angle range for horizontal lines and an angle range for verticallines. Alternatively, the correction unit 1330 may detect an anglerange, in which rectilinear lines that may be considered to behorizontal lines are maximally present, as an angle range for horizontallines, and may detect an angle range, in which rectilinear lines thatmay be considered to be vertical lines are maximally present, as anangle range for vertical lines.

At step 1723, the correction unit 1330 may include rectilinear lines,which correspond to one of the two angle ranges, in the set ofhorizontal lines or the set of vertical lines. More specifically, thecorrection unit 1330 may include a rectilinear line, which correspondsto the angle range for horizontal lines, in the set of horizontal lines.The correction unit 1330 may include a rectilinear line, whichcorresponds to the angle range for vertical lines, in the set ofvertical lines.

At step 1730, the correction unit 1320 may remove outliers from the setof horizontal lines and the set of vertical lines. The correction unit1320 may consider horizontal lines or vertical lines of the set ofhorizontal lines or the set of vertical lines, which correspond to apredetermined condition, to be outliers, and may remove the horizontallines or vertical lines, from the set of horizontal lines or the set ofvertical lines.

At step 1740, the correction unit 1320 may extract two horizontal linesfrom the set of horizontal lines, and may extract two vertical linesfrom the set of vertical lines.

The two horizontal lines may include a horizontal line closest to theorigin and a horizontal line farthest from the origin. The two verticallines may include a vertical line closest to the origin and a verticalline farthest from the origin.

At step 1750, the correction unit 1320 may detect four reference dots inthe set of at least one dot.

The four reference dots may be the intersections of the two horizontallines and the two vertical lines.

At step 1760, the correction unit 1320 may correct projection androtation distortion that have been applied to the set of at least onedot using the four reference dots.

For example, the correction unit 1320 may convert the region of the setof at least one dot so that the four reference dots become a rectanglecomposed of the horizontal lines and the vertical lines. Alternatively,the correction unit 1320 may convert an image of the target so that thefour reference dots become a rectangle composed of the horizontal linesand the vertical lines.

A process of performing correction on projection and rotation distortionthat have been applied to a set of at least one dot is described belowwith reference to FIG. 18.

FIG. 18 illustrates a process of performing correction on projection androtation distortion that have been applied to a set of at least one dotaccording to an example.

A first FIG. 1810 illustrates an image of the target obtained by theinformation extraction apparatus 200.

A second FIG. 1820 illustrates a graph illustrating central coordinatesto which Hough transform has been applied.

A third FIG. 1830 illustrates four reference dots extracted by thecorrection unit 1320.

A fourth FIG. 1840 illustrates an image of a target which uses the fourreference dots and to which the correction of projection and rotationdistortion has been applied.

FIG. 19 is a flowchart illustrating a method of performing correction onsize distortion that has been applied to a set of at least one dotaccording to an example.

Step 1620 described above with reference to FIG. 16 may include thefollowing steps 1910, 1920 and 1930.

At step 1910, the correction unit 1320 may generate a cumulative valuein a horizontal direction and a cumulative value in a vertical directionby accumulating values of the central coordinate of at least one dot inthe horizontal direction and the vertical direction.

At step 1920, the correction unit 1320 may detect a horizontal periodand a vertical period in which the at least one dot appears, byanalyzing the cumulative value in the horizontal direction and thecumulative value in the vertical direction.

The correction unit 1320 may detect a horizontal period and a verticalperiod in which the at least one dot appears by performing the frequencydomain analysis of the cumulative value in the horizontal direction andthe cumulative value in the vertical direction.

At step 1930, the correction unit 1320 may correct an image of the setof at least one dot so that the horizontal period and the verticalperiod match the original period. The correction unit 1320 may correctsize distortion that has been applied to the set of at least one dot bycorrecting the horizontal period and the vertical period according tothe original period.

The original period may refer to the interval at which at least one dotis disposed. The original period may include an original horizontalperiod and an original vertical period. The original horizontal periodmay refer to the horizontal interval at which at least one dot isdisposed. The original vertical period may refer to the verticalinterval at which at least one dot is disposed. The electronic data of atarget may include information about the original period. Alternatively,the information extraction apparatus 200 may receive information aboutthe original period from the information insertion apparatus 100, or mayreceive information about the original period through a user input.

A process of performing correction on size distortion that has beenapplied to a set of at least one dot is described below with referenceto FIG. 20.

FIG. 20 illustrates a process of performing correction on sizedistortion that has been applied to a set of at least one dot accordingto an example.

A first FIG. 2010 illustrates an image of the target whose projectionand rotation distortion have been corrected.

A second FIG. 2020 illustrates a graph in which the central coordinateof at least one dot has been accumulated in a horizontal direction and avertical direction.

A third FIG. 2030 illustrates frequency domain analysis.

A fourth FIG. 2040 illustrates an image of a target to which thecorrection of size distortion has been applied.

FIG. 21 is a flowchart illustrating a method of extracting informationfrom a set of at least one dot according to an example.

Step 1430 described above with reference to FIG. 14 may include thefollowing steps 2110 and 2120.

At step 2110, the extraction unit 1330 may determine one of a pluralityof different dot patterns that corresponds to each dot of a set of atleast one dot.

The extraction unit 1330 may determine one of the plurality of differentdot patterns that matches each dot as a dot pattern corresponding to thecorresponding dot.

For example, the form of a dot may not be identical with that of a dotpattern due to distortion applied to an image of the target or an imageof a set of at least one dot. The extraction unit 1330 may determine oneof the plurality of different dot patterns, having the highestcorrelation coefficient for each dot, as a dot pattern corresponding tothe corresponding dot. In this case, the correlation coefficient mayrefer to similarity between the form of a dot and the form of a dotpattern.

At step 2120, the extraction unit 1330 may use the value of the bitstring of the determined dot pattern as at least part of theinformation.

If a dot pattern corresponding to each dot of the set of at least onedot is determined, the extraction unit 1330 may identify a valuerepresented by each dot of the set of at least one dot. In this case,the value represented by each dot may be the value of a bit string.

FIG. 22 illustrates an electronic device that implements an informationinsertion apparatus according to an embodiment of the present invention.

The information insertion apparatus 100 may be implemented using as theelectronic device 2200 of FIG. 22.

The information insertion apparatus 100 may be implemented in a computersystem including a computer-readable recording medium. As illustrated inFIG. 22, the electronic device 2200 may include at least one processor2221, at least one piece of memory 2223, at least one user interface(UI) input device 2226, at least one UI output device 2227, and at leastone repository 2228 that communicate with each other via a bus 2222. Theelectronic device 2200 may further include a network interface 2229connected to a network 2230. The processor 2221 may be a centralprocessing unit (CPU) or semiconductor device configured to executeprocessing instructions stored in the memory 2223 or the repository2228. The memory 2223 and the repository 2228 may be a variety of typesof volatile or non-volatile storage media. For example, the memory mayinclude ROM 2224 or RAM 2225.

The electronic device 2200 may further include a printer 2240.

At least one module of the information, insertion apparatus 100 may bestored in the memory 2223, and may be configured to be executed by atleast one processor 2221. A function related to the communication of thedata or information of the electronic device 2200 may be performed viathe network interface 2229.

FIG. 23 illustrates an electronic device that implements an informationextraction apparatus according to an embodiment of the presentinvention.

The information extraction apparatus 200 may be implemented as theelectronic device 2300 of FIG. 23.

The information extraction apparatus 200 may be implemented in acomputer system including a computer-readable recording medium. Asillustrated in FIG. 23, the electronic device 2300 may include at leastone processor 2321, at least one piece of memory 2323, at least one UIinput device 2326, at least one UI output device 2327, and at least onerepository 2328 that communicate with each other via a bus 2322. Theelectronic device 2300 may further include a network interface 2329connected to the network 2330. The processor 2321 may be a semiconductordevice configured to execute processing instructions that are stored ina CPU, the memory 2323 or the repository 2328. The memory 2323 and therepository 2328 may be a variety of type of volatile or non volatilestorage media. For example, the memory may include ROM 2324 or RAM 2325.

The electronic device 2300 may further include a lighting device 2340and an image photographer 2350.

At least one module of the information extraction apparatus 200 may bestored in the memory 2323, and may be configured to be executed by theprocessor 2321. A function related to the communication of the data orinformation of the electronic device 2300 may be performed via thenetwork interface 2329.

As described above, the present invention provides a method, apparatus,and system for inserting information into a target and extractinginformation from a target.

There are provided a method, apparatus, and system using a barelyperceptible form or an imperceptible form in the insertion ofinformation and the extraction of information.

There are provided a method, apparatus, and system for correctinggeometric distortion that has been applied to an image of a target inthe extraction of information.

There are provided a method and apparatus for converting informationinto a set of at least one dot and adding the set of at least one dotindicative of the information to an electronic document.

There are provided a method and apparatus for converting informationinto a set of at least one dot and adding the set of at least one dotindicative of the information to a monitor screen.

At least one embodiment of the present invention may be implemented as acomputer program instructions that can be executed by various computermeans or various computer components. The computer-readable storagemedium may include program instructions, data files, and data structuressolely or in combination. The computer program instructions stored onthe storage medium may have been specially designed and configured forthe present invention, or may be known to or available to those who haveordinary knowledge in the field of computer software. Examples of thecomputer-readable storage medium include all types of hardware devicesspecially configured to record and execute program instructions, such asmagnetic media, such as a hard disk, a floppy disk, and magnetic tape,optical media, such as compact disk (CD)-read only memory (ROM) and adigital versatile disk (DVD), magneto-optical media, such as a flopticaldisk, ROM, random access memory (RAM), and flash memory. Examples of theprogram instructions include machine code, such as code created by acompiler, and high-level language code executable by a computer using aninterpreter. The hardware devices may be configured to operate as one ormore software modules in order to perform the operation of the presentinvention, and the vice versa.

Although the specific embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible without departing from the scope and spirit of the invention asdisclosed in the accompanying claims.

Therefore, the technical spirit of the present invention should not bedefined based on only the above-described embodiments, but should bedefined based on not only the attached claims but also all equivalentsto the attached claims.

What is claimed is:
 1. An information extraction method, comprising:identifying a set of at least one dot output to a target; extractinginformation from the set of at least one dot; and performing correctionon geometric distortion of the set of at least one dot, wherein:performing correction on the geometric distortion comprises performingcorrection on projection and rotation distortion of the set of at leastone dot; performing correction on the projection and rotation distortioncomprises detecting four reference dots in a region of the set of atleast one dot and performing correction on the projection and rotationdistortion using the four reference dots; and performing correction onthe projection and rotation distortion comprises generating a set ofhorizontal lines and a set of vertical lines passing through the atleast one dot, extracting two horizontal lines from the set ofhorizontal lines, and extracting two vertical lines from the set ofvertical lines; the four reference dots are intersections of the twohorizontal lines and the two vertical lines; the two horizontal linescomprise a horizontal line closest to an origin and a horizontal linefarthest from the origin; and the two vertical lines comprise a verticalline closest to the origin and a vertical line farthest from the origin.2. The information extraction method of claim 1, wherein identifying theset of at least one dot comprises detecting the set of at least one dotwithin the target by analyzing data of the target.
 3. The informationextraction method of claim 1, wherein identifying the set of at leastone dot comprises: capturing an image of the target; and detecting theset of at least one dot in the captured image.
 4. The informationextraction method of claim 3, further comprising emitting apredetermined type of light, which makes a substance, output to thetarget, perceptible, to the target.
 5. The information extraction methodof claim 1, wherein: performing correction on the projection androtation distortion comprises performing Hough transform on at least onecentral coordinate of the at least one dot; and horizontal lines andvertical lines passing through the at least one dot are horizontal linesand vertical lines passing through the at least one central coordinateto which the Hough transform has been applied.
 6. The informationextraction method of claim 1, wherein generating the set of horizontallines and the set of vertical lines comprises: detecting at least onerectilinear line passing through the at least one dot; detecting twoangle ranges in which the rectilinear lines are maximally present; andincluding the rectilinear lines, which correspond to one of the twoangle ranges, in the set of horizontal lines or the set of verticallines.
 7. The information extraction method of claim 1, furthercomprising performing correction on size distortion of the set of atleast one dot; wherein performing the correction on the size distortioncomprises: generating a cumulative value in a horizontal and acumulative value in a vertical direction by accumulating values of thecentral coordinates of the at least one dot in the horizontal directionand the vertical direction; detecting a horizontal period and a verticalperiod, in which the at least one dot appears, by analyzing thecumulative value in the horizontal direction and the cumulative value inthe vertical direction; and correcting an image of the set of at leastone dot so that the horizontal period and the vertical period match anoriginal period.
 8. The information extraction method of claim 7,wherein the horizontal period and the vertical period are detected byfrequency domain analysis of the cumulative value in the horizontaldirection and the cumulative value in the vertical direction.
 9. Theinformation extraction method of claim 1, wherein extracting theinformation comprises: for each dot of the set of at least one dot,determining a dot pattern that corresponds to the each dot among aplurality of different dot patterns; and using a value of a bit stringof the determined dot pattern as at least part of the information. 10.An information extraction apparatus, comprising: a hardware processorconfigured to identify a set of at least one dot output to a target, toextract information from the set of at least one dot, and to performcorrection on size distortion of the set of at least one dot by:generating a cumulative value in a horizontal and a cumulative value ina vertical direction by accumulating values of the central coordinatesof the at least one dot in the horizontal direction and the verticaldirection; detecting a horizontal period and a vertical period, in whichthe at least one dot appears, by analyzing the cumulative value in thehorizontal direction and the cumulative value in the vertical direction;and correcting an image of the set of at least one dot so that thehorizontal period and the vertical period match an original period.